It is often desirable to determine the valence state of a selected target atom for material analysis. Valence state signifies with greater precision the chemical makeup of a sample. Different valence states of the same element are known to react differently in their environments, therefore, determining valence state can be useful in, e.g., medical diagnostics. Valence state differences from sample-to-sample can also be used to comparatively detect different sources of the material for, e.g., forensics. The present invention is directed to this problem of detecting different valence states.